Check in codegen test expectations.

test/codegen/expect/lib/math/coin_test.js

Index: test/codegen/expect/lib/math/coin_test.js
diff --git a/test/codegen/expect/lib/math/coin_test.js b/test/codegen/expect/lib/math/coin_test.js
new file mode 100644
index 0000000000000000000000000000000000000000..4b00a2908ca146ded25e3c7b19e1cef5038365c9
--- /dev/null
+++ b/test/codegen/expect/lib/math/coin_test.js
@@ -0,0 +1,56 @@
+dart_library.library('lib/math/coin_test', null, /* Imports */[
+  'dart_sdk',
+  'expect'
+], function load__coin_test(exports, dart_sdk, expect) {
+  'use strict';
+  const core = dart_sdk.core;
+  const math = dart_sdk.math;
+  const dart = dart_sdk.dart;
+  const dartx = dart_sdk.dartx;
+  const expect$ = expect.expect;
+  const coin_test = Object.create(null);
+  let VoidTodynamic = () => (VoidTodynamic = dart.constFn(dart.definiteFunctionType(dart.dynamic, [])))();
+  coin_test.main = function() {
+    let seed = math.Random.new().nextInt(1 << 16);
+    core.print(dart.str`coin_test seed: ${seed}`);
+    let rnd = math.Random.new(seed);
+    let heads = 0;
+    let tails = 0;
+    for (let i = 0; i < 10000; i++) {
+      if (dart.test(rnd.nextBool())) {
+        heads++;
+      } else {
+        tails++;
+      }
+    }
+    core.print(dart.str`Heads: ${heads}\n` + dart.str`Tails: ${tails}\n` + dart.str`Ratio: ${heads / tails}\n`);
+    expect$.Expect.approxEquals(1.0, heads / tails, 0.1);
+    heads = 0;
+    tails = 0;
+    for (let i = 0; i < 10000; i++) {
+      rnd = math.Random.new(i);
+      if (dart.test(rnd.nextBool())) {
+        heads++;
+      } else {
+        tails++;
+      }
+    }
+    core.print(dart.str`Heads: ${heads}\n` + dart.str`Tails: ${tails}\n` + dart.str`Ratio: ${heads / tails}\n`);
+    expect$.Expect.approxEquals(1.0, heads / tails, 0.1);
+    heads = 0;
+    tails = 0;
+    for (let i = 0; i < 10000; i++) {
+      rnd = math.Random.new();
+      if (dart.test(rnd.nextBool())) {
+        heads++;
+      } else {
+        tails++;
+      }
+    }
+    core.print(dart.str`Heads: ${heads}\n` + dart.str`Tails: ${tails}\n` + dart.str`Ratio: ${heads / tails}\n`);
+    expect$.Expect.approxEquals(1.0, heads / tails, 0.1);
+  };
+  dart.fn(coin_test.main, VoidTodynamic());
+  // Exports:
+  exports.coin_test = coin_test;
+});